text: /*
   * include/common/initcall.h
   *
   * Initcall management.
   *
   * Copyright (C) 2018 Willy Tarreau - w@1wt.eu
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
   * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #ifndef _COMMON_INIT_H
  #define _COMMON_INIT_H
  
  /* List of known init stages. If others are added, please declare their
   * section at the end of the file below.
   */
  enum init_stage {
  	STG_PREPARE = 0,      // preset variables, tables, list heads
  	STG_LOCK,             // pre-initialize locks
  	STG_ALLOC,            // allocate required structures
  	STG_POOL,             // create pools
  	STG_REGISTER,         // register static lists (keywords etc)
  	STG_INIT,             // subsystems normal initialization
  	STG_SIZE              // size of the stages array, must be last
  };
  
  /* This is the descriptor for an initcall */
  struct initcall {
  	void (*const fct)(void *arg1, void *arg2, void *arg3);
  	void *arg1;
  	void *arg2;
  	void *arg3;
  };
  
  /* Declare a static variable in the init section dedicated to stage <stg>,
   * with an element referencing function <function> and arguments <a1..a3>.
   * <linenum> is needed to deduplicate entries created from a same file. The
   * trick with (stg<STG_SIZE) consists in verifying that stg if a valid enum
   * value from the initcall set, and to emit a warning or error if it is not.
   * The function's type is cast so that it is technically possible to call a
   * function taking other argument types, provided they are all the same size
   * as a pointer (args are cast to (void*)). Do not use this macro directly,
   * use INITCALL{0..3}() instead.
   */
  #define __DECLARE_INITCALL(stg, linenum, function, a1, a2, a3)     \
          static const struct initcall *__initcb_##linenum           \
  	    __attribute__((__used__,__section__("init_"#stg))) =   \
  	        (stg < STG_SIZE) ? &(const struct initcall) {      \
  		.fct = (void (*)(void *,void *,void *))function,   \
  		.arg1 = (void *)(a1),                              \
  		.arg2 = (void *)(a2),                              \
  		.arg3 = (void *)(a3),                              \
  	} : NULL
  
  /* This is used to resolve <linenum> to an integer before calling
   * __DECLARE_INITCALL(). Do not use this macro directly, use INITCALL{0..3}()
   * instead.
   */
  #define _DECLARE_INITCALL(...) \
  	__DECLARE_INITCALL(__VA_ARGS__)
  
  /* This requires that function <function> is called with pointer argument
   * <argument> during init stage <stage> which must be one of init_stage.
   */
  #define INITCALL0(stage, function)                                     \
  	_DECLARE_INITCALL(stage, __LINE__, function, 0, 0, 0)
  
  /* This requires that function <function> is called with pointer argument
   * <argument> during init stage <stage> which must be one of init_stage.
   */
  #define INITCALL1(stage, function, arg1)                               \
  	_DECLARE_INITCALL(stage, __LINE__, function, arg1, 0, 0)
  
  /* This requires that function <function> is called with pointer arguments
   * <arg1..2> during init stage <stage> which must be one of init_stage.
   */
  #define INITCALL2(stage, function, arg1, arg2)                         \
  	_DECLARE_INITCALL(stage, __LINE__, function, arg1, arg2, 0)
  
  /* This requires that function <function> is called with pointer arguments
   * <arg1..3> during init stage <stage> which must be one of init_stage.
   */
  #define INITCALL3(stage, function, arg1, arg2, arg3)                   \
  	_DECLARE_INITCALL(stage, __LINE__, function, arg1, arg2, arg3)
  
  /* Iterate pointer p (of type initcall**) over all registered calls at
   * stage <stg>.
   */
  #define FOREACH_INITCALL(p,stg)                                               \
  	for ((p) = &(__start_init_##stg); (p) < &(__stop_init_##stg); (p)++)
  
  /* Declare a section for stage <stg>. The start and stop pointers are set by
   * the linker itself, which is why they're declared extern here. The weak
   * attribute is used so that we declare them ourselves if the section is
   * empty. The corresponding sections must contain exclusively pointers to
   * make sure each location may safely be visited by incrementing a pointer.
   */
  #define DECLARE_INIT_SECTION(stg)                                                   \
  	extern __attribute__((__weak__)) const struct initcall *__start_init_##stg; \
  	extern __attribute__((__weak__)) const struct initcall *__stop_init_##stg
  
  /* Declare all initcall sections here */
  DECLARE_INIT_SECTION(STG_PREPARE);
  DECLARE_INIT_SECTION(STG_LOCK);
  DECLARE_INIT_SECTION(STG_ALLOC);
  DECLARE_INIT_SECTION(STG_POOL);
  DECLARE_INIT_SECTION(STG_REGISTER);
  DECLARE_INIT_SECTION(STG_INIT);
  
  /* not needed anymore */
  #undef DECLARE_INIT_SECTION
  
  /* Run the initcalls for stage <stg>. The test on <stg> is only there to
   * ensure it is a valid initcall stage.
   */
  #define RUN_INITCALLS(stg)                                                     \
  	do {                                                                   \
  		const struct initcall **ptr;                                   \
  		if (stg >= STG_SIZE)                                           \
  			break;                                                 \
  		FOREACH_INITCALL(ptr, stg)                                     \
  			(*ptr)->fct((*ptr)->arg1, (*ptr)->arg2, (*ptr)->arg3); \
  	} while (0)
  
  #endif /* _COMMON_INIT_H */
  
  /*
   * Local variables:
   *  c-indent-level: 8
   *  c-basic-offset: 8
   * End:
   */
  